I think the painting on the dress top is flat. How can I paint this without it looking flat? decorations?
For realism, you can use textures (these are cc0). You can modify the color using nodes in the shader editor (mixRGB or hue saturation), paint a mask to differentiate between the green and white fabric, and bake it out as a base either to have a uv’d texture or as a base for further texturing. You can also check out Dikko’s tutorials on texturing, for a more stylized approach, or to combine with realistic textures for depth.